Wallboard tape



1954 P. CHRISTMAN 2,667,822

WALLBOARD TAPE Filed Sept. 6, 1951 3 SheetsSheet l REWINDING\ Fig. 2

Ea ..1 Q J y NEEDLE'PERFORATING SANDING SKIVING UNWINDING IN V EN TOR. Paul' Chr/szman P. CHRISTMAN Feb. 2, 1954 WALLBOARD TAPE 3 Sheets-Sheet 2 Filed Sept. 6, 1951 INVE NTOR. Paul Chr/sfman ATTORNEY Feb. 2, 1954 P. CHRISTMAN 2,667,822

WALLBOARD TAPE Filed Sept. 6, 1951 v 3 Sheets-Sheet 5 INV'ENTOR. Paul Chrlsfman WS-W Patented Feb. 2, 1954 UNITED STATES PATENT OFFICE Bemiss-Jason Company, San Francisco, GaiiL, 'a partnership composed of R. P. Bemiss and W. Jason Application-September 6, 1851,Serial, No..245,389

2 Claims. .1

' This invention relates to improvements in .wall board tape and provides a novel .form of tape, as well as a method of making it, resulting .in reduced cost of manufacture, reduced cost 'of installation and a better Joint Ethan attainable with conventional forms of wall .board tape.

Wall board tape is primarily .used in dry-wall construction in order .to ,produce a smooth, generally invisible joint between .abutting wall board panels, suitable .for subsequent painting or wall papering.

I-n dry wall construction, wallpanels of standard dimension are nailed .to the studs, preterab'ly in such .a way, that adjoining ,panels abut over a stud. Wall board panels are ,generally slightly tapered along the .long edges .and the nails are driven through the board .into the stud within the tapered portions. A vjoint compound is then .applied over the abutting tapered portions with a broad iknife which is-drawn along the joint .so as to ,produce -a compound .surface whichfis substantiallyfius'h with the non-bevelled surface portion of the abutting .panels.

.A length of wall -board tape is then applied over the compound simply by placing it over the compound and drawing the broad :knife-over the tape, causing the back surface of *thetape to adhere to the compound. In order to permit :air bubbles to escapeirom behind the tape, conventional wall board tape isperiorated-with the-exception ofithe edge portions. Theedges aregenerally s'kived iinorder Itomake the edgesof the tape inconspicuous.

The perforations in conventional wall hoard tape are produced by ,punching, and each :hole has a diameter of the order .of between and is of an inch. As the'broad knife is drawnover the tape in order to press the tape-into engagement with .a compound, the compound ;'is {compressed to some extent, as the flexible .blade of 'the broad .kni'fe ,passes .along the tape. The pressure thus ,produced .causes a certain :amount of compound to now through the ,perforations "behind the edge of themovingbroad knife. The compound which ,passes through the holes forms pimples which then harden .and can :only ibe .removed'by sanding.

Repeated passage of the broad knifeover the tape in order toremovethe pimples before :hardening does .not produce -.a ,perfectlytsmooth .sur- Taco, since each time pressure 'is built -.up in the compound underneath the .knife edge causing further compound to .flow through the perforations immediately .after the .edge of the :knife has passed. The pimples, however .small, are conspicuous, particularly the wall painted, unless theyareremoved lay-sanding. Sandinglis .a, time consuming and dusty :special operation which increaseszconstructionrcost.

formation of compound pimpleshy reducing the size of the perforations to 511011 an extent that compound ispreventedirom passing through the perforations, while ,yet leaving the tape .su'fiiciently pert/ions to permit trapped air to escape. In this connection it has been proposed to form the perforations. in the 'tape ."by electric hischarges. .The resulting tape is called "fispark tape in the trade and .is quite .efiective in ,preventing passage of compound through the perforations. The main diffmulty in the manufacture of spark tape, however, ,is the relative slowness with which the perforations can he produced. If the tape is advanced at too .rap'ida rate, the .holes, instead of being around become elongated, or even. .become .slits, which is objectionable. The sparking .of the tape thus lbecomes the slowest step .in its manufacture, subsequent steps, .such as :skiving .of the edges, .being operations which can %be producedata much .fasterrate.

The invention provides .a novel Zform .of wall "board joint tape with perforations .small enough to prevent the passage .of .compound there- .through, but .capable of ibeing produced at .a considerably faster rate than the spark tape, the operation --of perforating 'being carried out as rapidly as the tape can .beskiued.

Ehe resulting Ztape .has .numerous physical characteristics which make it superior to iother formsof tapes now .in-existence, as willhe pointed out hereinafter. These characteristics generally contribute to the iormationzof a moresecure bond of the tape to the compound, greater case 05:. application and an even less 'conspicuous Joint than .is ,produceable with aconventional ztape, particularly in instances where a joint is to be produced between non-.bevelledtboardsedges.

These and various .other objects, .features and advantages of the invention will :appear :more fully from :the detailed description which follows, accompanied by draw-ings ishowing, -for the .purpose :of illustration, a preferred embodiment of invention and .steps in themethod of producing it. The invention thus :Jconsi'sts in certain new :and original features of construdtion as well *as new and original steps and sequences of *steps hereinafter set forth and "claimed.

Although the characteristic features of this invention which are believed to be novel will 'be particularly pointed out in the claims appended hereto, the "invention itself, its .(ibj ects and .advantages, and the .man'ner .iin which .it may .be carried out may he better .understood .by referring to the following description' taken tin :connection-with the-accompanying drawingsiiomnn ia part .ofitrin which:

Figure 1 is a diagrammatic seleuaitional wiew illustrating :steps zinithe :prnduetion nf ithe novel Attempts have Joeen :made .to *eliminate 15118 6 tape;

U Figure 2 is a diagrammatic plan view of Fi ure 1; I

Figures 3 to 6 are perspective views of portions of tape at the various stages of manufacture;

Figures '7 to 9 are greatly enlarged sectional views of portions of the tape shown in Figures 4 to 6 respectively; and

Figure 10 is a perspective view illustrating one art will permit. Corresponding reference char acters refer to corresponding parts in the several figures of the drawings.

In the drawings accompanying, and forming part of, this specification, certain specific disclosure of the invention is made for the purpose of explanation of broader aspects of the invention, but it is understood that the details may be modified in various respects without departure from the principles of the invention, and that the invention may be applied to other forms of tape than the one shown.

Wall board tape is generally of a width of the order of two inches, it being obvious that narrower or wider tape can be used where special circumstances call for it.

A reel of tape H is supported on a shaft l2, and tape I3 is withdrawn from the reel in the direction indicated by the arrow [4.

The tape [3, at this stage, is a parallel-edged strip of paper stock, generally calendered to a relatively smooth surface on both sides.

The tape l3, after passing between guide rollers and [6, passes into the nip of a needle point perforator consisting of a needle roller H and a pressure roller 48 urging the tape against the surface of the needle roller. The needle roller preferably is a metal roller beyond the surface [9 of which individual needles project slightly. A good grade of phonograph needle is quite suitable for this purpose.

The pressure roller 18 preferably has a metal core 2| over which a facing 22 of a resilient material is applied. Natural or synthetic rubber are suitable as facing. The life of the rubber is surprisingly long even though the needles extend into it slightly as the tape l3 passes through the pm.

The needles are so set that, as the tape passes through the nip of the rollers I! and I 8, the

needles pierce the tape and extend slightly into.

the resilient facing of the pressure roller l 8.

Thus, the tape l3 leaving the nip of the rollers I1, I 8 has many small perforations extending through it. Referring to Figures 4 and '7, it is seen, that the perforations are unique, in that no stock is actually removed from the tape. In distinction, each perforation is bounded by a de pression 23 from which a more or less funnelshaped aperture 24 extends. The walls 25 of the funnel are produced by a displacement or upsetting of the surrounding paper fibers.

The paper fibers of the stock remote from the perforation are substantially parallel to the surfaces 26 and 21. In distinction, the upset fibers have a greater normal component of direction with respect to the tape surface. This is illustrated in Figure 7 where the direction of the undisturbed fibers is indicated at 28 whereas upset fibers are indicated at 29.

Since the formation of the apertures amounts to a local deformation of the paper stock, the dis- 4 placed stock appears in the form of a substantially annular protuberance 30 rising slightly above the back surface 21 of the tape.

These protuberances are removed or reduced in the next operation. For this purpose the perforated tape I3 is passed over a sander 3|, against which the tape is urged by a pressure roller 32. The sanding roller 3! practically removes the protuberances 3% from the back surface of the tape. However, if the tape is examined closely, particularly under a magnifying glass, a small annular area 33 is noticeable around each aperture 2d. The actual height of this area over the back surface is microscopic, and the area 33 is noticeable primarily because of the change in direction of the fibers.

The sander is so constructed and adjusted that it not only reduces the protuberances 3!] but also uniformly roughens the back surface 2! to produce a ground back surface 2?. The ground surface area 27? remote from the apertures 24 appears to have a slightly different texture than the area 33. This is mainly due to the fact that fibers remote from the aperture 2% lie substantially parallel to the back surface and. are roughened or loosened, whereas the fibers lie more or less normal within the area 33 where they are cut off substantially at right angles to the direction of the fibers. This primarily produces the annular raised appearance of the area 33, when the tape is viewed from the back.

The perforated and ground tape I3" is then skived to reduce the thickness of the edges of the tape. This skiving may be done in various ways, but the preferred manner of skiving is by means of two grinding wheels 34 and 35. The wheels 34 and 35 are dressed to a slight taper as shown with considerable exaggeration in Figure 2. A pressure plate 36 properly spaces the tape from the surface of the wheels 3t and 35, a preferred adjustment being that in which the thickness of the tape is reduced to about onehalf at the edges. Thus, a ten-caliper tape is skived to five-caliper at the edges. The skiving operation also uniformly roughens the top surface of the tape within the skived areas 37, but the center area of the tape 26 remains smooth and calendered.

The tape IS' is then rewound on a rewinding reel supported on a shaft 39. The tape 13" may pass between guide rollers 40 and M on its way to the rewinding reel.

Considering now the use of the tape, its physical characteristics and its advantages, a typical installation is shown in Figure 10. Two Wall board panels 82 and 53 are nailed to a stud 44 by nails 45. The wall board panels closely abut, or are slightly spaced at 52, it being immaterial whether a small space remains between the edges of the panels, since any space at this point will be filled with a joint compound. The wall panels 42 and 43 are shown as having tapered edges 46 and 41. v

After the nailing of the panels, a joint compound is applied over the tapered areas 46 and 47, preferably with a broad knife 48. The compound generally is a water-mixed composition which, during application, has the consistency of putty, and which, after several hours, hardens to a stone-like substance. The compound adheres well to paper, such as the paper ply d9 of the wall board. The compound also adheres Well to the core material 50, in the event a portion of the paper ply is removed, as it happens along the edges of a cut panel. 7

The surface of the compound is made substantially flush with the surface of the panels 42 and 43, before the tape [3" is applied. The surface of the compound may be made slightly convex, plane, or slightly concave, depending on the force exerted on the thin and flexible broad knife. Greater pressure naturally tends to make the surface of the compound concave. Slight concavity is quite desirable as it compensates for the thickness of the tape to be applied.

The joint tape I3 is then applied by pressing it with its back surface against the soft compound. The roughened back surface 21 of the tape adheres extremely well to the compound as the tape is pressed into adhesive engagement with the compound by the broad'knife.

The force of the blade, and the resultant pressure locally built up in the compound does not cause the compound to fiow through the apertures. This is due to two reasons:

Firstly, the apertures are small. Secondly, the area 33 immediately adjacent each aperture appears to have capillary properties tending to withdraw a certain amount of moisture from the compound which would tend to fiow through the aperture. This promotes more rapid setting of the compound at the apertures and effectively stops the flow of compound into and through the apertures.

Thus, the formation of compound pimples is effectively prevented and a subsequent sanding operation of the tape joint is made entirely unnecessary.

Frequently, joints must be made between nontapered edges of panels, particularly where cut panels are used. Reduced panel widths are usually produced by scoring the wall board and then breaking it along the score line.

Joints of non-tapered edges are naturally thicker than the board itself. In order to make such joints as inconspicuous as possible, it is good practice to make the joint considerably Wider than a joint between tapered edges. Tape of the same width is used for such wide joints, but a certain amount of compound is applied to either side of the tape in order to produce a surface which tapers so gradually into the surface of the panels as to be imperceptible. In joints of this type it is naturally desirable to keep compound from adhering to the center portion of the tape where the joint is thickest. The smooth calendered surface portion 26 of the tape I3" is readily stripped clean of compound by passage of the broad knife over it. However, the compound adheres readily to the skived areas 31, where it is desired to adhere in order to form a gradually tapered surface merging into the surface of the wall board at some distance from the joint proper.

It is thus seen that the physical qualities of the novel tape are very advantageous. Among these properties are:

The smallness of the size of the perforations;

The capillary characteristics within the area The uniformly roughened back surface 21;

The uniformly roughened front areas 31; and

The smooth calendered center area 26.

The novel tape is very economical to produce since the tape can be perforated as fast as it can be ground and skived. The production rate attainable with a new tape is therefore considerably higher than the production rate of spark ape.

Obviously, the present invention is not limited to the specific form disclosed nor to the specific sequence of steps illustrated and described. Various details may be modified and various additions, omissions, substitutions or other changes made without departing from the spirit of the invention.

What is claimed is:

1. A paper tape for wall board joints, comprising a substantially parallel-edged strip of paper having a front surface and a back surface, the front surface having a smooth raised center portion along which the fibers lie flat with respect to the tape surface, and tapered edge portions to either side of the center portion along which the surface is rougher than at the center portion so that, within the edge portion, surface fibers, at least in part, stand up with respect to the tape surface, the thickness of the tape decreasing towards the edges from the raised center portion, the back surface being flat from edge to edge and having a rough finish across its entire width so that surface fibers, at least in part, stand up with respect to the back surface, the tape having pin prick perforations therethrough, each perforation being characterized by a depression around the perforation, said depression extending from the front surface, the direction of the fibers immediately surrounding each perforation having a greater normal component with respect to the tape surface than fibers remote from the perforation, the fibers surrounding each perforation terminating in a plane substantially parallel to the back surface of the tape.

2. In the method of converting paper tape into wall board joint tape, the steps, which comprise, pin-pricking the tape at spaced points to displace, without punching out of stock, the paper fibers which normally extend substantially parallel to the tape surface into a new direction in which such displaced fibers, at least in part, have a greater normal component of direction with regard to the tape surface than fibers not so displaced, such displacement of the fibers breaking the continuity of the tape surface resulting in holes which on one side are characterized by a cavity with respect to the tape surface and on the opposite side by an annular protuberance of displaced fibers; flat grinding the opposite surface from edge to edge to roughen it and to reduce said protuberances; and then grinding a marginal strip of the one surface along each edge at an angle to the central portion of said one surface to feather the edge, leaving the surface between said marginal strips undisturbed.

PAUL CI-IRISTMAN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,602,597 Staude Oct. 12, 1926 1,967,726 Sherman July 24, 1934 2,047,982 Page July 21, 1936 2,138,383 Little et al. Nov. 29, 1938 2,180,433 Page et a1 Nov. 21, 1939 2,181,530 Davenport Nov. 28, 1939 2,218,674 Eaton Oct. 22, 1940 2,294,966 Dreyfus Sept. 8, 1942 2,316,054 Davis et al Apr. 6, 1943 2,518,838 Tempe Aug. 15, 1950 

